The present invention relates to techniques for determining track origin in a cigarette making machine.
Filter tip cigarettes are generally made in pairs in cigarette making machines. In such machines a filter tip has a tobacco column wrapped in paper applied to each end. The filter tip is fixed in place by wrapping a filter tipping paper about the filter and the end of each of the two tobacco columns. The whole rod is then placed into a slitter, which cuts the rod at the centre of the filter plug to form two cigarettes. Such a machine thus produces two lines of cigarettes simultaneously. The cigarettes are ejected onto a transport system known as a mass flow.
In order to increase the speed of cigarette manufacture, twin track cigarette making machines have been produced, in which a second making track is incorporated into the machine. Each of the tracks produces two lines of cigarettes, in the way described above. The cigarettes from both tracks are mixed in the mass flow.
In cigarette making machines, quality control measures are usually taken, and adjustments are made to the machine to ensure that the cigarettes meet the required specification. In addition, a further quality control step is usually employed, whereby a sample of cigarettes is selected from the mass flow and subjected to more stringent tests. When performing such tests, it may be desirable to know the line and track from which the cigarette originates.
WO 2004/083834 discloses a technique for determining the direction of wrapping of cigarette wrapping paper. In a single-track machine, the cigarettes in the mass flow may be wrapped either clockwise or counter-clockwise. By determining the wrapping direction, it may be possible to identify the line from which the cigarette originates.
However, using existing techniques, it is not possible to determine the track from which a cigarette originates in a twin-track cigarette making machine once the cigarette is mixed in the mass flow.